Research support

Soy versus Meat-based Weight Loss Diets

grant holder
Prof. Dr. Alexandra Johnstone
university
- University of Aberdeen, Rowett Institute of Nutrition and Health

Hunger and appetite responses were compared in 20 healthy, obese men consuming a high soy protein weight loss diet versus a meat based high-protein weight loss diet.

Background

  • Previous work has indicated that high-protein (30% of diet as protein) meat-based weight loss diets are highly satiating, and reduce the free food intake over a four-week period (1,2).
  • There is limited data on assessing the effect of different types of protein on appetite in weight loss studies (3). Previously, a mixed meat source of protein was used in our high protein diets, but this approach has been criticised both from a policy and public health perspective because of potential negative side effects, especially on gut health (4).
  • There is acceptance that plant based weight loss diet may offer protection from diseases (5).
  • It may be that alternative plant-based sources of protein could be satiating, and yet maintain a healthy gut during weight loss, and we set up a study to test this, using soy protein

Research undertaken: a human dietary intervention study investigating protein induced satiety during weight loss, using soy protein.

We compared hunger and appetite responses in 20 healthy, obese men eating a vegetarian high-protein weight loss diet and a meat based high-protein weight loss diet. All meals were provided as 30% protein, 30% fat and 40% carbohydrate from energy, to provide basal energy requirements. Appetite bio-markers like plasma amino acid profile and gut hormones were monitored in response to a test meal challenge which reflects the impact of the diet on volunteers’ satiety. (http://www.ncbi.nlm.nih.gov/pubmed/24944057).

Main findings and concluding remarks

  • Over the two weeks, subjects lost similar amounts of weight, on average 2.41 and 2.27 kg on the vegetarian high-protein weight loss and meat based high-protein weight loss diets respectively, with similar reduction in fat-mass and preservation of fat-free mass, due to the high protein component.
  • The vegetarian high-protein weight loss had a similar impact on appetite and motivation to eat as the meat based high-protein weight loss diet.
  • Blood biomarkers improved with weight loss for both high protein diets (plasma cholesterol, low density lipoproteins (LDL), high density lipoproteins (HDL), triglycerides and glucose)
  • There was a greater reduction in total cholesterol with the plant based diet for cholesterol and LDL cholesterol. This finding could be attributed to the composition of soy-based meals, (i.e. fibre, phytochemicals, and other micro- and macronutrients).
  • Since appetite control and weight loss was similar in both weight loss diets, plant-based high-protein diet could be a healthier alternative to meat based high-protein weight loss diets, achieving desired results without any negative health effects (e.g. risk of colonic disease).

Publication:

Neascu M, Fyfe C, Horgan G, Johnstone AM. Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial. Am J Clin. Nutr. 2014 Jun 18; 100(2):548-558.

 

References:

  1. Westerterp-Plantenga MS, et al. Annu Rev Nutr 2009; 29:21-41.
  2. Johnstone AM, et al. Am J Clin Nutr 2008; 87(1):44-55.
  3. Due A, et al. Int J Obes Rel Metab Disord 2004; 28(10):1283-90.
  4. Russell WR, et al.. Am J Clin Nutr 2011; 93(5):1062-1072.
  5. Clifton P. Brit J Nutr 2012; 108:122–129.

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